The rating level: What is it and is it a suitable setvalue for the acoustic quality of office workplaces?

In German speaking countries, the so-called rating level (Lr) is an important set value in the field of occupational health and safety. Lr is a parameter to measure the magnitude of sound immission during the evaluation period Tr and takes into account supplements or deductions for specific sounds, times or situations. Lr is applied to workplaces characterized by activities with different requirements (e.g. concentrated vs. automated work) and focuses on the prevention of extra-aural effects. The measurement of Lr is described in DIN 45645-2: 2012 and set values are defined in VDI 2058:2014. However, it is surprising to see that almost no studies exist, where Lr has been varied in order to investigate the impact of sounds differing with regard to Lr onto well-being, performance or health. Therefore, the set values defined in VDI 2058:2014 are lacking any scientific basis. But Lr can easily be calculated retrospectively if the experimental sounds are available and thus it is possible to reanalyze data using Lr as a predictor of noise effects. The reported study explains the concept of Lr. It also provides results of a reanalysis of experimental data based on the application of Lr. The results indicate that the set values defined in VDI 2058:2014 need to be questioned. However, Lr. also has some potential to be reasonable connected to the current research on the Speech Transmission Index (STI) and distraction distance (rD) with regard to noise effects at workplaces.